Is AFR just calcium?

[Ballyhoo]

I have a Red Sea Reef dose 2 and in one pump I have the AFR, and the other is for magnesium. It wasn't until I started testing for magnesium that I stopped having coral die. It is a 52 gallon system, but with all the rock work, coral and fish I'm guessing it's probably 40 gallons. right now if I dose 13 mg of AFR daily my calcium approaches 470 ppm. But if I failed to dose magnesium and alkalinity, they fall below acceptable ranges. For example it wasn't until I started dosing magnesium that I had better coral health. I have to dose 1.5 mg of magnesium a day to maintain a magnesium of lower 1300s. A couple of days ago I tested my alkalinity and it was way down to 6.7. I guess my alkalinity dropped because I backed down on the AFR as my calcium levels had been approaching 500. So I've been back to manually dosing alkalinity over the course of last few days. I've had to dose about 8 mg to bring it up to about 7.2. Of course this concerns me because I wanna go on vacation and I like things done automatically so I don't have to worry about them. I don't know if I would add some alkalinity to my ATO when I leave for a week and estimate how much alkalinity I would need to add. I know that's not an ideal situation due to evaporation variations but I would have to guesstimate. Other than that, I'm just wondering is AFR just totally high in calcium and the makers of this product have underestimated the amount of alkalinity and magnesium that most tanks need? Is there a better product that would have higher magnesium and alkalinity values with calcium all in one? I doubt it. I haven't seen any at LFS. I guess I might have to buck up and spend big money for the Red Sea 4. I purchased the Jebao on Ali baba , or ali express whatever it's called auto dosing pump with four heads, but I don't trust it. I don't know if anyone has any experience with the Jaebao because they say you're usually get what you pay for and this was like only $100. But ultimately my question is why does AFR have so much calcium and so little magnesium and alkalinity to ratio? Is there an alternative product? Also does anyone have any knowledge the Jebao doser they sell on Ali baba on the cheap?

also, my salt mix is blue bucket.

thanks for anyone's comments, thoughts!!

Post script: I just tested my magnesium and it's at 1410. Dosing 1.5 mg a day. It dosed at 8 AM which is about six hours ago, so now I have to figure out the exact amount of magnesium to dose. i'm not sure how my magnesium crept up so high.

 

[Randy Holmes-Farley]

AFRhas the exact balanced of calcium to alk that pure calcium carbonate does. That ends up being a tiny bit excess calcium in terms of matching consumption. It is identical to kalkwasser in that respect.

AFR also contains magnesium. Whether it is enough mag to offset demand depends o. How much of your alk demand comes from coralline algae (uses more mag) and how much from typical corals (use less). If all the demand came from coralline, it has about half of what is consumed, but in all cases that excess demand will not be more than about 1 ppm mag per day.

FWIW, I’d use just AFR unless calcium got over 550 ppm.

 

[lawnerd]

My understanding is that AFR has calcium formate which is supposed to provide balanced alkalinity and calcium.

Is there something in a reef tank that consumes alkalinity without consuming calcium? That may explain why alkalinity is dropping but calcium is increasing.

 

[Dread Pirate Dave]

From their site.

Tropic Marin | Aquarium | Produktinformationen

Tropic Mairn - The aquatic life science company. Wir stellen hochwertige Salze, Additive und Wassertests vorwiegend für Meerwasseraquarien her. Korallen, Fische und Wirbellose in Ihrem Aquarium fühlen sich mit unseren Produkten wohl.

www.tropic-marin-smartinfo.com

Note:
In some cases, calcium and alkalinity may be consumed in different ratios than from the coral’s needs alone. If this occurs, and parameters become unbalanced, use the chart to make the proper corrections.

 

[VintageReefer]

The alkalinity from all for reef isn’t measurable immediately. It takes approx 24 hours after dosing to develop

 

[Ballyhoo]

The alkalinity from all for reef isn’t measurable immediately. It takes approx 24 hours after dosing to develop

that may be the case, but I've been dosing AFR continuously for months. Perhaps you're point Is That daily adjustments of AFR won't have an immediate impact.

So Randy states that I can go up to 55O of Ca+? I thought 500 was a limit to avoid precipitation.and that's why I was backing off. Also what happens if magnesium goes over 1400? and what is the absolute lower end acceptable for Alk? Yes, Coralign. I seem to have plenty of it. I don't know what to do about it if I should scrape some and get rid of some.

really appreciate the info.

 

[Randy Holmes-Farley]

My calcium recommendation is 40@-550 ppm, and nothing magic happens a bit higher.

In terms of precipitation, a rise in pH of 0.3 units (say, 8.1 to 8.4) is like a doubling of calcium (say, 400 to 800 ppm). So pH is a far bigger driver of precipitation than is calcium.

 

[rtparty]

Dose AFR, do 10% weekly water changes, and don’t worry about calcium or magnesium. Just base dosing off alkalinity. Calcium and magnesium will level out and the water changes keep either from rising or falling too much

 

[gbroadbridge]

that may be the case, but I've been dosing AFR continuously for months. Perhaps you're point Is That daily adjustments of AFR won't have an immediate impact.

So Randy states that I can go up to 55O of Ca+? I thought 500 was a limit to avoid precipitation.and that's why I was backing off. Also what happens if magnesium goes over 1400? and what is the absolute lower end acceptable for Alk? Yes, Coralign. I seem to have plenty of it. I don't know what to do about it if I should scrape some and get rid of some.

I've been using AFR for my Nano tank for 3 years.

Alk is stable at 8dkh and Ca rose to about 550pm and stayed there a long time before dropping to around 520 recently.

I'd simply dose based on keeping Alk stable and ignore Ca and Mg.

 

[Ballyhoo]

well, I've done some of the suggestions in the above posts, but I got deficient in magnesium down to the low 1100 . I had coral die so I don't know how to explain that I guess I could've dosed up the AFR. But I didn't wanna go over 500.

 

[rishma]

well, I've done some of the suggestions in the above posts, but I got deficient in magnesium down to the low 1100 . I had coral die so I don't know how to explain that I guess I could've dosed up the AFR. But I didn't wanna go over 500.

If you are testing magnesium with a home test kit, test error is highly likely. On the other hand, magnesium dropping that low while using AFR is highly unlikely. Just trying to help. Cheers.

 

[Ballyhoo]

If you are testing magnesium with a home test kit, test error is highly likely. On the other hand, magnesium dropping that low while using AFR is highly unlikely. Just trying to help. Cheers.

it got low though. i had unpredictable coral issues until I used my Salifert mg test kit and started dosing 1.5 mg a day. my CA though was up to 490. so something is using mg. i'm dosing every day 13 mg of AFR and calcium is like 460. So I don't feel like I have a lot of room to dose above 14 mg of AFR. My KH is down to about 6.7 without dosing alkalinity. I mean, I can't argue with the numbers of the tests. I bought several salifert kits just to make sure that one wasn't bad. The numbers are consistent. so again if I just dose 14 mg of AFR every day, my calcium would be about 460, alkalinity would be about 6.7 and magnesium probably would be down 11 or 1200. So what's the situation here? I don't understand I'm supposed to just increase my AFR to get calcium above 500?

 

[rishma]

it got low though. i had unpredictable coral issues until I used my Salifert mg test kit and started dosing 1.5 mg a day. my CA though was up to 490. so something is using mg. i'm dosing every day 13 mg of AFR and calcium is like 460. So I don't feel like I have a lot of room to dose above 14 mg of AFR. My KH is down to about 6.7 without dosing alkalinity. I mean, I can't argue with the numbers of the tests. I bought several salifert kits just to make sure that one wasn't bad. The numbers are consistent. so again if I just dose 14 mg of AFR every day, my calcium would be about 460, alkalinity would be about 6.7 and magnesium probably would be down 11 or 1200. So what's the situation here? I don't understand I'm supposed to just increase my AFR to get calcium above 500?

I am going to provide a long reply. I recognize it’s a lot, but I genuinely hope this helps.

I cannot comment on the coral issues, there are too many variables which could have nothing to do with calcium, alkalinity or magnesium. I can comment on the chemistry. I am going to assume your salinity is correct, but you should make certain, because low salinity can cause low measurements of major elements and result in you chasing your tail.

Magnesium
Magnesium home kits are so inaccurate many of us do not test at home, ever. There is literally a new thread in this forum every day seeking help with magnesium issues because of inaccurate test results in home kits. This thread is worth a read.

Just say NO to magnesium testing: RMM is born

OK, this thread has been many years in the making, and I'm posting it here since folks in the chem forum are probably already tired of all the threads relating to problematic magnesium testing. I'm going to propose a method, let's call it the Randy Magnesium Method, or RMM for short. All good...

www.reef2reef.com

Chemistry of calcification in a reef tank
For every 2.8 dKH of alkalinity consumed, about 18-20 ppm of calcium is consumed and 1-2 ppm of magnesium is consumed. There is a range because, for example, a tank with heavy coraline algae growth will consume closer to 2 ppm magnesium while a tank with mostly coral growth will consume closer to 1 ppm magnesium for each 2.8 dKH alkalinity consumed. Magnesium consumption is about 5-10% of calcium consumption. There are many references for this but I won’t dig them up right now because this is already a long post.


AFR chemistry
AFR provides alkalinity/calcium/magnesium in these proportions:

2.8dkH/20ppm/0.9ppm.

Pretty close to the proportions used in a reef tank.

AFR alkalinity
The best practice is to dose AFR based on alkalinity tests to match alkalinity consumption. This is preferred over calcium tests because alkalinity kits are more accurate and smaller changes are more easily observed. If you do that, it provides plenty of calcium and usually enough magnesium for most tanks (more on this below). The following is based on the assumption that the AFR dose is matching the alkalinity consumption and keeping alkalinity stable.

Calcium in AFR
AFR over-supplies calcium just a little bit, like 1-2ppm for each 2.8 dKH dosed. Over time, calcium levels can build up in a tank at 1-2ppm for each 2.8dkH that is dosed (and consumed). In your tank with a 14ml per day AFR dose to 52 gallons, calcium can build up 1-2ppm per week. This means is takes 1-2 years increase calcium levels by 100ppm assuming no water changes.

Randy says 550ppm calcium is acceptable. I’ve had a tank at 600ppm based on ICP tests that was healthy.

AFR Magnesium
Based on the reef calcification chemistry and the chemistry of AFR, the magnesium provided by AFR is just below the bottom of the range of consumption if alkalinity is kept stable. That is close enough for most tanks. For most people this never becomes an issue because reef salts are generally high in magnesium and the occasional water change is sufficient to keep it in range even if consumption is at the higher end.

Here is a breakdown of why I think your Magnesium measurement is likely inaccurate (again, assuming your salinity is correct).

You are dosing 14 ml (milliliters) of AFR to your 52 gallon system. This means you are dosing about 0.4dkH, 2.9 ppm Ca, 0.13 ppm Mg. Assuming your alkalinity is stable, this means you are consuming 0.4 dKH, 2.6-2.9 ppm Ca, 0.14-0.28ppm Mg.

The maximum difference between your Magnesium provided by AFR and consumed by calcification is ~0.15ppm per day.

If we assume your saltwater started at 1320ppm Magnesium (reasonable for salt mixed to 1.026) then it would take 4 years to drop to 1100 ppm if your magnesium consumption was at the high end of the range and you did no water changes.

I know of no other significant use of magnesium in a reef except calcification, so that is why I think test error is likely.

 

[gbroadbridge]

I mean, I can't argue with the numbers of the tests.

Assuming you are performing the tests correctly, you can still argue with the test results because home tests for Mg have been proven to be extremely unreliable and inaccurate.

I would only dose AFR based on Alk consumption, never Ca as it cannot be measured accurately in most tanks.

If you have any coral issues, they are most likely to be completely unrelated to chemistry provided that your salinity is accurate and you are performing regular water changes. Look elsewhere such as light and flow.

 

[Ballyhoo]

I don't understand so I shouldn't even buy calcium and magnesium tests? if salifert shows me 580 Ca and alk 8.0 i'm done?

I think my concern is the amount of Coraline is difficult to measure also. And the few achro i have, I'm not sure what they're mostt consuming. A lot of torch though.

excellent information from everyone thank you

also, sounds like no one here has anything more than a single doser. But when I go to LFS they have four dosers. Mind you we're talking large tanks with huge amounts of coral.

it really does seem like putting my expensive coral at risk though for example if I dose AFR to bring my ALK up to 8.0, but then my magnesium was down to like 1100s.

 

[rishma]

I don't understand so I shouldn't even buy calcium and magnesium tests? if salifert shows me 580 Ca and alk 8.0 i'm done?

I’m not sure I fully understand the question but I would not buy or use a magnesium test kit.

I personally do not test calcium at home. I use AFR and occasionally send an ICP so I get an accurate view of my calcium (and magnesium) a couple times per year which is sufficient since I use AFR and I know how much is being dosed.

I test alkalinity regularly. Everything else is based on the math I described earlier.

 

[Ballyhoo]

I am going to provide a long reply. I recognize it’s a lot, but I genuinely hope this helps.

I cannot comment on the coral issues, there are too many variables which could have nothing to do with calcium, alkalinity or magnesium. I can comment on the chemistry. I am going to assume your salinity is correct, but you should make certain, because low salinity can cause low measurements of major elements and result in you chasing your tail.

Magnesium
Magnesium home kits are so inaccurate many of us do not test at home, ever. There is literally a new thread in this forum every day seeking help with magnesium issues because of inaccurate test results in home kits. This thread is worth a read.

Just say NO to magnesium testing: RMM is born

OK, this thread has been many years in the making, and I'm posting it here since folks in the chem forum are probably already tired of all the threads relating to problematic magnesium testing. I'm going to propose a method, let's call it the Randy Magnesium Method, or RMM for short. All good...

www.reef2reef.com

Chemistry of calcification in a reef tank
For every 2.8 dKH of alkalinity consumed, about 18-20 ppm of calcium is consumed and 1-2 ppm of magnesium is consumed. There is a range because, for example, a tank with heavy coraline algae growth will consume closer to 2 ppm magnesium while a tank with mostly coral growth will consume closer to 1 ppm magnesium for each 2.8 dKH alkalinity consumed. Magnesium consumption is about 5-10% of calcium consumption. There are many references for this but I won’t dig them up right now because this is already a long post.


AFR chemistry
AFR provides alkalinity/calcium/magnesium in these proportions:

2.8dkH/20ppm/0.9ppm.

Pretty close to the proportions used in a reef tank.

AFR alkalinity
The best practice is to dose AFR based on alkalinity tests to match alkalinity consumption. This is preferred over calcium tests because alkalinity kits are more accurate and smaller changes are more easily observed. If you do that, it provides plenty of calcium and usually enough magnesium for most tanks (more on this below). The following is based on the assumption that the AFR dose is matching the alkalinity consumption and keeping alkalinity stable.

Calcium in AFR
AFR over-supplies calcium just a little bit, like 1-2ppm for each 2.8 dKH dosed. Over time, calcium levels can build up in a tank at 1-2ppm for each 2.8dkH that is dosed (and consumed). In your tank with a 14ml per day AFR dose to 52 gallons, calcium can build up 1-2ppm per week. This means is takes 1-2 years increase calcium levels by 100ppm assuming no water changes.

Randy says 550ppm calcium is acceptable. I’ve had a tank at 600ppm based on ICP tests that was healthy.

AFR Magnesium
Based on the reef calcification chemistry and the chemistry of AFR, the magnesium provided by AFR is just below the bottom of the range of consumption if alkalinity is kept stable. That is close enough for most tanks. For most people this never becomes an issue because reef salts are generally high in magnesium and the occasional water change is sufficient to keep it in range even if consumption is at the higher end.

Here is a breakdown of why I think your Magnesium measurement is likely inaccurate (again, assuming your salinity is correct).

You are dosing 14 ml (milliliters) of AFR to your 52 gallon system. This means you are dosing about 0.4dkH, 2.9 ppm Ca, 0.13 ppm Mg. Assuming your alkalinity is stable, this means you are consuming 0.4 dKH, 2.6-2.9 ppm Ca, 0.14-0.28ppm Mg.

The maximum difference between your Magnesium provided by AFR and consumed by calcification is ~0.15ppm per day.

If we assume your saltwater started at 1320ppm Magnesium (reasonable for salt mixed to 1.026) then it would take 4 years to drop to 1100 ppm if your magnesium consumption was at the high end of the range and you did no water changes.

I know of no other significant use of magnesium in a reef except calcification, so that is why I think test error is likely.

I think I need to spend a day or so studying this post. but I will point out again since I have started testing magnesium I haven't had any coral death. That's been about two months. and so Randy, the king of chemistry, has a single doser? Boy the learning curve in this hobby. I'm glad I haven't gone out and bought the expensive Red Sea four doser.

 

[rtparty]

I think I need to spend a day or so studying this post. but I will point out again since I have started testing magnesium I haven't had any coral death. That's been about two months. and so Randy, the king of chemistry, has a single doser? Boy the learning curve in this hobby. I'm glad I haven't gone out and bought the expensive Red Sea four doser.

Even if you decide to get a multi head doser, don't do the Red Sea

 

[Ballyhoo]

Even if you decide to get a multi head doser, don't do the Red Sea

Is the Jebao ok?

 

[rishma]

I don't understand so I shouldn't even buy calcium and magnesium tests? if salifert shows me 580 Ca and alk 8.0 i'm done?

I think my concern is the amount of Coraline is difficult to measure also. And the few achro i have, I'm not sure what they're mostt consuming. A lot of torch though.

excellent information from everyone thank you

also, sounds like no one here has anything more than a single doser. But when I go to LFS they have four dosers. Mind you we're talking large tanks with huge amounts of coral.

it really does seem like putting my expensive coral at risk though for example if I dose AFR to bring my ALK up to 8.0, but then my magnesium was down to like 1100s.

I have 6 dosers and dose many things. I think Randy has multiple dosers too.

I understand you want to believe your home magnesium test. I’d you are not comfortable with the chemistry I outlined the only other thing I can suggest is sending your water to a reputable ICP test vendor to get accurate results and move forward.

There are multiple ways to dose a tank. You don’t need to use AFR. Best of luck.